depression, feeling like you are afraid of gaining weight ect.
It affects the outside of your body from your weight and how it changes, throughout the way you deal with it, after you eat you end up vomiting it which causes the body to remove the food out of the body if it continues it could lead long term issues.
It affects your body when you start to vomit which can affect your teeth and you might end up having a facial swelling, all of these should start happening once you start purging you could end up harming your body.
The cause of it is unknown
-psychological counseling and sometimes medicines like antidepressants .
If a person with bulimia constantly is worrying about their weight, encourage them and tell them that they are not fat and that they are beautiful just the way they are.